Method for producing optical information recording medium

ABSTRACT

A method for producing an optical information recording medium includes the steps of: coating a solution for forming a dye recording layer onto a surface of a rotating disc-shaped resin substrate; and discharging a cleaning solution from a nozzle onto a peripheral edge to remove the dye recording layer from the peripheral edge, wherein discharge of the cleaning solution is initiated 1.0 to 300 seconds after completion of the coating, and the nozzle is disposed on a plane that extends in a normal line direction of the substrate and includes a straight line representing a discharge direction of the cleaning solution, so that an angle defined by the discharge direction and the normal line is 0 to 60°.

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a method for producing anoptical information recording medium, and more particularly, to a methodfor producing an optical information recording medium that includes adisc-shaped resin substrate having a peripheral edge disposed with annon-recording region.

[0003] 2. Description of the Related Art

[0004] A CD-R is a writable, optical information recording medium(optical disc) on which information can be written only once byirradiation with laser light, and is widely known. CD-Rs areadvantageous in that, in comparison with conventional CDs in whichinformation is recorded by forming pits on a substrate by injectionmolding, a small number of CDs can be manufactured rapidly and at areasonable cost. Moreover, the demand for CD-Rs has been escalatingrecently with the spread of personal computers.

[0005] CD-Rs typically comprise a transparent disc substrate havingsuccessively disposed thereon a recording layer formed of an organicdye, a metallic (e.g., gold) reflective layer, and a resin protectivelayer. Information is recorded on the optical disc by irradiating theoptical disc with a laser in the near infrared region (ordinarily laserlight having a wavelength in the vicinity of 780 nm). Specifically, theportion of the dye recording layer that is irradiated absorbs the light,whereby temperature increases at the irradiated portion. The localincrease in temperature deforms the recording layer (e.g., to form pits)at the irradiated portion, whereby information is recorded. The recordedinformation is ordinarily reproduced by irradiating the optical discwith a laser having the same wavelength as that of the laser used torecord the information, and by detecting a difference in reflectancebetween the region of the recording layer that has been thermallydeformed (recorded portion) and the region of the recording layer thathas not been deformed (unrecorded portion).

[0006] Recently, writable digital versatile discs (DVD-Rs) have alsobeen put to practical use as media having a larger recording capacitythan CD-Rs. DVD-Rs typically comprise two transparent disc substratesthat each have successively disposed thereon a recording layer formed ofan organic dye, a reflective layer, and a resin protective layer, withthe discs being adhered together so that the recording layers faceinward, or comprise the transparent disc substrate and a protectivesubstrate having the same disc shape as the disc substrate that areadhered together. In each transparent disc substrate, there is formed aguide groove (pre-groove) for tracking laser light irradiated duringrecording. The pre-groove has a width (0.74 to 0.8 μm) that is equal toor less than half the width of the pre-groove of a CD-R.

[0007] The outer peripheral edge of a CD-R or DVD-R is a non-recordingregion where no dye recording layer is disposed. The purpose of thenon-recording region is to improve the outer appearance of the disc bycovering the dye recording layer with the reflective layer, and toenhance adhesion by directly adhering the protective layer to thesubstrate. The dye recording layer is formed by spin-coating a dyesolution onto the surface of the substrate and drying the dye solution.However, although it is possible to initiate spin coating so that thespin coater begins coating from a somewhat limited position at the innerperiphery of the substrate, it is difficult to control the range ofcoating towards the outer periphery. For this reason, the dye recordinglayer is generally first disposed on the entire surface of thesubstrate, and then cleaning solution is jetted onto the dye recordinglayer at the outer peripheral edge to remove the dye recording layerfrom the outer peripheral edge and create the non-recording region.

[0008] There are generally two ways that the non-recording region isformed in this manner during the process of producing the optical disc.One is by washing/removing the dye recording layer immediately after ithas been formed, and the other is by washing/removing the dye recordinglayer after both it and the reflective layer have been formed. Below,the former may be called “earlier washing” and the latter may be called“later washing”.

[0009] In the case of earlier washing, there are problems in thatdroplets of the cleaning solution may be scattered onto portions of therecording layer that are not to be removed, whereby those portions aredissolved and recording errors occur at those portions during recordingor playback.

[0010] In the case of later washing (i.e., when the dye recording layeris formed by spin-coating the dye solution onto the surface of thesubstrate and allowing the dye solution to dry, and washing is conductedafter the reflective layer is formed only on the recording region of thedye recording layer), the non-recording region is formed by washing onlythe portion of the recording layer disposed at the outer peripheraledge, where the reflective layer is not formed. However, practicalproblems arise in that the shape of the edge of the recording layer maybecome irregular depending upon washing conditions. In addition, becausetime lapses after coating the dye recording layer, there is the problemthat it takes time wash the recording layer.

[0011] It is possible to prevent the cleaning solution from beingscattered and adhering to the dye recording layer by preforming thenon-recording region by spin-coating the dye solution onto the surfaceof the substrate except for the outer peripheral edge and allowing thedye solution to dry to thereby form the dye recording layer, and thenwashing after the reflective layer has been formed on the dye recordinglayer. However, because it is difficult to control the range of coatingtowards the outer periphery of the substrate, the dye recording layerintrudes into the area where the substrate and the reflective layershould ordinarily be closely adhered together, which reduces adhesionbetween the substrate and the reflective layer. When adhesion is reducedin this manner, water or oxygen may intrude from outside into the dyerecording layer, whereby storage stability of the recording medium isreduced.

SUMMARY OF THE INVENTION

[0012] The present invention was devised in view of the precedingproblems in the prior art. It is an object of the invention to provide amethod for producing an optical information recording medium in whichcleaning solution is prevented from being scattered and adhering to adye recording layer when the dye recording layer is removed from anouter periphery of the medium by washing, to thereby efficiently form anon-recording region and produce an optical information recording mediumthat has excellent storage stability and excellent recording andplayback characteristics.

[0013] This object is achieved by the following means.

[0014] According to a first aspect of the invention, there is provided amethod for producing an optical information recording medium, comprisingat least the steps of: coating a solution for forming a dye recordinglayer onto a surface of a rotating disc-shaped resin substrate; anddischarging a cleaning solution from a nozzle onto a peripheral edge toremove the dye recording layer from the peripheral edge, whereindischarge of the cleaning solution is initiated 1.0 to 300 seconds aftercompletion of the coating, and the nozzle is disposed on a plane thatextends in a normal line direction of the substrate and includes astraight line representing a discharge direction of the cleaningsolution, so that an angle defined by the discharge direction and thenormal line is 0 to 60°.

[0015] According to a second aspect of the invention, there is provideda method for producing an optical information recording medium,comprising at least the steps of: coating a solution for forming a dyerecording layer onto a surface of a rotating disc-shaped resinsubstrate; coating a reflective layer on the formed dye recording layer;and discharging a cleaning solution from a nozzle onto a peripheral edgeto remove the dye recording layer from the peripheral edge, whereindischarge of the cleaning solution is started 1.0 to 300 seconds aftercompletion of the coating of the reflective layer, and the nozzle isdisposed on a plane that extends in a normal line direction of thesubstrate and includes a straight line representing a dischargedirection of the cleaning solution, so that an angle defined by thedischarge direction and the normal line is 0 to 60°.

BRIEF DESCRIPTION OF THE DRAWINGS

[0016]FIG. 1 is a schematic sectional view illustrating a spin coaterused in embodiments of the present invention.

[0017]FIG. 2 is an enlarged sectional view of a washing device and awaste recovery device used in the embodiments.

[0018]FIG. 3 is an enlarged sectional view illustrating a washing devicethat is different from the washing device illustrated in FIG. 2.

[0019]FIG. 4 is a plan view for illustrating a position at which anozzle is disposed relative to a substrate.

[0020]FIGS. 5A to 5D are sectional views illustrating steps in a processfor producing an optical disc in accordance with a first embodiment ofthe invention.

[0021]FIG. 6 is a sectional view illustrating the structure of a generalCD-R disc.

[0022]FIG. 7 is a plan view illustrating the manner in which coatingsolution is spun off.

[0023]FIG. 8 is a plan view illustrating the manner in which coatingsolution is spun off.

[0024]FIG. 9 is a sectional view illustrating a position at which thenozzle is disposed when washing a non-recording region.

[0025]FIG. 10 is a plan view illustrating a position at which the nozzleis disposed when washing the non-recording region.

[0026]FIGS. 11A to 11D are sectional views illustrating steps in aprocess for producing an optical disc in accordance with a secondembodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] Hereinafter, embodiments of a method for producing an opticalinformation recording medium according to the present invention will beexplained in detail with reference to the drawings.

[0028]FIG. 1 is a sectional view of a spin coater 10 used in the methodof the invention. As illustrated in FIG. 1, the spin coater 10 comprisesan applicator 11, a spinner head 13, a wall 15 for preventing scatter,an exhaust device 19, a washing device 21, and a waste recovery device24. The spin coater 10 illustrated in FIG. 1 can coat a dye recordinglayer and remove the dye recording layer from an outer peripheral edgeof a disc resin substrate 1.

[0029] The applicator 11 comprises a nozzle 12 that includes a pressuretank (not illustrated) and a valve (not illustrated) for controllingdischarge amount. The nozzle 12 drops a predetermined amount of coatingsolution onto a surface of the substrate 1. The applicator 11 is movedby means of a handling mechanism (not illustrated) from a standbyposition to a predetermined position above the substrate 1. The spinnerhead 13 is disposed below the applicator 11, includes a detachablefixing member 14 for keeping the substrate 1 horizontal, and is rotatedby a drive motor (not illustrated). The substrate 1 is rotated by thespinner head 13 so that coating solution dropping onto the substrate 1from the nozzle 12 is horizontally flown across the surface of thesubstrate 1 toward the outer periphery of the substrate 1 to form acoating film. Excess coating solution is spun away from and runs off ofthe outer peripheral edge of the substrate. Once the coating solutionfilm has dried, a coating film is formed on the surface of the substrate1. The wall 15 prevents excess coating solution (waste solution)spinning off from the outer peripheral edge of the substrate 1 frombeing scattered around the substrate 1. The wall 15 is disposed aroundthe spinner head 13, with an opening 16 being formed above the spinnerhead 13.

[0030] Waste solution collects in a pan 17 disposed beneath the wall 15and is recovered through a drain 18. The exhaust device 19 allows air tocirculate in from the opening 16, over the surface of the substrate 1,and then to below the spinner head 13. The exhaust device 19 includes avalve (not illustrated) for adjusting exhaust amount and a fan 20. Byadjusting the amount of exhaust (speed of exhaust), drying conditionsfor the coating film can be changed.

[0031] The washing device 21 comprises two nozzles 22 and 23 thatinclude a pressure tank (not illustrated) and a value (not illustrated)for adjusting discharge amount. The two nozzles 22 and 23 jet cleaningsolution at a predetermined pressure onto the outer peripheral edge ofthe dye recording layer on the substrate 1, and can discharge thecleaning solution independently. Washing can therefore be performedusing either one or both of the nozzles 22 and 23. Similar to theapplicator 11, the washing device 21 is moved by a handling mechanism(not illustrated) from a standby position to a predetermined positionduring washing, and can alter the direction in which the cleaningsolution is discharged.

[0032] The washing device 21 will be now be described in detail withreference to FIGS. 2 to 4. FIG. 2 is an enlarged sectional viewillustrating the washing device 21 and the waste recovery device 24.FIG. 3 is an enlarged sectional view illustrating a washing device 21′that is different from the washing device illustrated in FIG. 2. FIG. 4is a schematic plan view illustrating a position at which the nozzle 22is disposed. FIGS. 2 and 3 are each views seen from the side of a planeextending in a normal line direction of the substrate 1 (i.e.,orthogonal to the substrate 1) and including a straight linerepresenting the direction in which the cleaning solution is dischargedfrom the nozzles 22 and 23.

[0033] As illustrated in FIG. 2, the nozzles 22 and 23 are bent so thatthe cleaning solution is obliquely jetted onto the substrate 1. However,the configuration of the nozzles 22 and 23 is not limited to theconfiguration shown in FIG. 2 as long as the conditions below concerningthe discharge direction of the cleaning solution are met.

[0034] For preventing the cleaning solution from splattering, asillustrated in FIG. 2, the nozzles 22 and 23 are disposed so that anglesθ₁, θ₂, which are defined by the intersection between a normal lineL_(n), of the substrate 1 and directions L_(a) and L_(b) in which thecleaning solution is discharged from the nozzles 22 and 23, are each 0to 60°, and preferably 10 to 45°. The angle at which the nozzles 22 and23 are bent is adjusted to meet this condition.

[0035] Although the nozzles 22 and 23 illustrated in FIG. 2 are bent,they may have, for example, a straight configuration such as nozzles 22′and 23′ in FIG. 3. In order to discharge the cleaning solution withinthe angle range described below, the nozzles 22′ and 23′ are connectedto the spin coater 10 via a valve (not illustrated) having anangle-adjusting function or a member (not illustrated) having anangle-adjusting function.

[0036] As illustrated in FIG. 3, the nozzles 22′, 23′ are disposed sothat angles θ₁, θ₂, which are defined by the intersection between thenormal line L_(n) of the substrate 1 and directions L_(a) and L_(b) inwhich the cleaning solution is discharged from the nozzles 22′ and 23′,are each 0 to 60°, and preferably 10 to 45°. The angle at which thenozzles 22′ and 23′ are disposed is adjusted to meet this condition.

[0037] Although the bent nozzles 22 and 23 and the straight nozzles 22′and 23′ discharge the cleaning solution in the above-described anglerange, they are at least disposed so that the discharge direction of thecleaning solution is directed away from the center of the substrate 1.In addition, the range of the angles θ₁ and θ₂ is defined on the planeextending in a normal line direction of the substrate 1 and includingthe straight line representing the direction in which the cleaningsolution is discharged.

[0038] As illustrated in FIG. 4, the nozzle 22 (and 23 or 22′ and 23′)is, when seen from above, additionally disposed so that an angle θ₃,which is defined by the intersection between a straight line L_(d)connecting the center of the substrate 1 with a mouth of the nozzle 22and a cleaning solution discharge direction L_(c) facing in thedirection of rotation R, is preferably 0 to 60°, and more preferably 10to 45°.

[0039] In addition, the distance between the mouth of the nozzle 22 (or23, 22′, 23′) and the substrate 1 is preferably 0.3 to 5.0 mm, morepreferably 0.5 to 3.0 mm, and even more preferably 0.7 to 2.0 mm. Thediameter of the nozzle is preferably 0.1 to 0.8 mm, and more preferably0.2 to 0.6 mm, in order to stably discharge the cleaning solution.

[0040] Although description has been given of the washing device 21,which is disposed with an upper nozzle (22) and a lower nozzle (23) ,the washing device 21 may be one disposed with only one nozzle. In thiscase, the washing device 21 preferably includes a handling mechanism tomove the one nozzle so that the coating solution is discharged from bothabove and below the outer peripheral edge of the substrate 1 (thecoating film). The washing device 21 may also be disposed with manynozzles. However, because increasing the number of nozzles results in anincrease in the amount of cleaning solution used and may cause moresplattering of the cleaning solution, the number of nozzles ispreferably 1 to 4, and more preferably 1 or 2. Also, since the method ofthe invention includes two washing steps, the diameter of the nozzle andthe number of nozzles may be changed for each step.

[0041] In order to recover the post-wash liquid (containing the cleaningsolution and the dye-containing components removed by that cleaningsolution), the waste recovery device 24 includes a drain 26 having anopening 25 that faces the direction in which the liquid is scattered. Asseen in FIGS. 1 and 2, the waste recovery device 24 is independentlydisposed so that the drain 26 is accommodated within the drain 18.Accordingly, the post-wash liquid (waste liquid) is gathered into theopening 25 and is recovered through the drain 26 separately from thewaste coating solution. It is to preferable to dispose the wasterecovery device 24 with a mechanism for vertically moving the wasterecovery device 24. By moving the waste recovery device 24 to a lowerstandby position when the dye recording layer is being formed, the wastecoating solution (e.g., the scattered dye-containing coating solution)can be recovered without being obstructed by the waste recovery device24.

[0042] Method for Producing Optical Disc (1)

[0043] Description will now be given of a first embodiment of the methodof the invention applied to the spin coater 10 (FIG. 1) disposed withthe washing device 21 and waste recovery device 24. FIGS. 5A to 5Dillustrate steps in the method, which in this embodiment is for formingthe non-recorded region by earlier washing.

[0044]FIG. 6 illustrates an optical disc (CD-R) 30 comprising thedisc-shaped transparent resin substrate 1 having successively disposedthereon a dye recording layer 2, a reflective layer 3, and a protectivelayer 4. Because this type of optical disc is common, the method will bedescribed using the optical disc 30 as an example. However, the methodcan also be applied to a DVD-R.

[0045] Examples of material usable for the substrate 1 includepolycarbonate, acrylic resins such as polymethyl methacrylate, vinylchloride resins such as polyvinyl chloride and vinyl chloride copolymer,epoxy resins, amorphous polyolefins, and polyester. These materials maybe concurrently used as desired. The material used is preferablytransparent. In particular, polycarbonate is preferable in view ofresistance to moisture, dimensional stability, and cost.

[0046] The substrate 1 includes a guide groove for tracking or apre-groove representing information such as address signals. Thepre-groove is preferably formed directly in the substrate when the resinmaterial is injection molded or extrusion molded, and preferably has adepth 0.01 to 0.3 μm and a half width of 0.2 to 0.9 μm.

[0047] On the surface of the substrate 1 at the side at which the dyerecording layer 2 is disposed, an undercoat layer may be provided forthe purpose of improving flatness and adhesive force, and preventingdeterioration of the dye recording layer 2. Examples of suitablematerial for the undercoat layer include macromolecular materials suchas polymethyl methacrylate, acrylic acid/methacrylic acid copolymer,stylene/maleic anhydride copolymer, polyvinl alcohol, N-methylolacrylamide, stylene/vinyltoluene copolymer, chlorosulfonatedpolyethylene, nitrocellulose, polyvinyl chloride, chlorinatedpolyolefin, polyester, polyimide, vinyl acetate/vinyl chloridecopolymer, ethylene/vinyl acetate copolymer, polyethylene,polypropylene, polycarbonate, and a surface modifier such as a silanecoupling agent. The undercoat layer can be formed by dissolving ordispersing the material into a suitable solvent to prepare a coatingsolution, and thereafter coating the coating solution onto the surfaceof the substrate by spin-coating, dip-coating, or extrusion-coating. Thethickness of the undercoat layer is generally 0.005 to 20 μm, andpreferably 0.01 to 10 μm.

[0048] As illustrated in FIG. 5A, the dye recording layer 2 is disposedon the substrate 1 using the spin coater 10 according to the invention.When the dye recording layer 2 is formed, the washing device 21 and thewaste recovery device 24 have been moved to standby positions byhandling mechanisms (not illustrated) so that they do not becomeobstacles. The substrate 1 is mounted on, for example, the spinner head13 illustrated in FIG. 1, and horizontally held in place by the fixingmember 14. Next, coating solution supplied from the pressure tank (notillustrated) is adjusted to a predetermined amount by the valve (notillustrated) and dropped onto the inner periphery of the substrate 1through the nozzle 12. Here, the coating solution is a dye solution inwhich a dye has been dissolved in a suitable solvent. The concentrationof the dye in the coating solution is generally 0.01 to 15 mass %,preferably 0.1 to 10 mass %, more preferably 0.5 to 5 mass %, and mostpreferably 0.5 to 3 mass %.

[0049] The spinner head 13 is drivingly rotated by the drive motor athigh speed, whereby coating solution falling onto the substrate is spunacross the surface of the substrate 1 and towards the outer periphery ofthe substrate 1 to form a coating film. Excess coating solution is spunoff of the substrate 1 by centrifugal force, scattered around thesubstrate 1, collides against the wall 15, is collected in the pan 17,and is thereafter recovered through the drain 18. FIG. 7 is a typicalview illustrating excess coating solution (indicated by the arrows),which has reached the outer periphery of the substrate 1, beingomnidirectionally spun off of the substrate 1 by centrifugal force,scattering around the substrate 1, and colliding against the wall. Thecoating film is dried by the exhaust device 19 during and after theprocess of forming the coating film. The thickness of the coating film(the dye recording layer) is generally 20 to 500 nm, and preferably 50to 300 nm.

[0050] The dye used in the dye recording layer is not particularlylimited. Examples thereof include cyanine dyes, phthalocyanine dyes,imidazo-quinoxaline dyes, pyrylium/thiopyrylium dyes, azulenium dyes,squalirium dyes, metallic complex salt dyes such as Ni or Cr,naphthoquinone dyes, anthraquinone dyes, indophenol dyes, indoanilinedyes, triphenylmethane dyes, merocyanin dyes, oxonol dyes,aluminum/diimmonium dyes, and nitroso-compounds. Of these dyes, cyaninedyes, phthalocyanine dyes, azulenium dyes, squalirium dyes, oxonol dyes,and imidazo-quinoxaline dyes are preferable.

[0051] Examples of the solvent for the coating solution for forming thedye recording layer include: esters such as butyl acetate or cellosolveacetate; ketones such as methyl ethyl ketone, cyclohexanone or methylisobutyl ketone; chlorinated hydrocarbons such as dichloromethane,1,2-dichloroethane or chloroform; amides such as dimethyl formamide;hydrocarbon such as cychlohexane; ethers such as tetrahydrofuran,ethylether, or dioxane; alcohols such as ethanol, n-propanol,isopropanol, n-butanol, or diacetone alcohol; fluorine-containingsolvents such as 2,2,3,3-tetrafluoropropanol; glycol ethers such asethylene glycol monomethyl ether, ethylene glycol monoethyl ether, orpropylene glycol monomethyl ether. These may be used singly or incombination of two or more, in consideration of the solubility of thedye. The solvent is preferably a fluorine-containing solvent such as2,2,3,3-tetrafluoropropanol. Other additives may be included as neededin the coating solution, such as anti-fading agents, binding agents,antioxidants, UV absorbents, plasticizers, and lubricants.

[0052] Examples of the anti-fading agent include nitroso compounds,metal complexes, diimmonium salts, and aminium salts, which aredescribed in Japanese Patent Application Laid-Open (JP-A) Nos. 2-300288,3-224793, and 4-146189.

[0053] Examples of the binding agent include: natural organic highpolymers, such as gelatin, cellulose derivatives, dextran, rosin, andrubber; and synthetic organic high polymers, such as hydrocarbon resins,such as polyethylene, propylene, polystyrene and polyisobutylene, vinylresins, such as polyvinyl chloride, polyvinylidene chloride, and apolyvinyl chloride/polyvinyl acetate copolymer, acrylic resins, such aspolymethyl acrylate and polymethyl methacrylate, and also polyvinylalcohol, chlorinated polyethylene, epoxy resins, butyral resins, rubberderivatives, and initial condensation products of thermosetting resinslike phenol/formaldehyde resins. When a binding agent is used, theamount thereof is generally 0.2 to 20 parts by mass, preferably 0.5 to10 parts by mass, and more preferably 1 to 5 parts by mass, based upon100 parts by mass of the dye.

[0054] Next, as illustrated in FIG. 5B, cleaning solution is jetted fromthe nozzle 22 onto the outer peripheral edge of the formed dye recordinglayer 2, whereby the dye recording layer 2 is washed/removed from theouter peripheral edge (earlier washing). The handling mechanisms (notillustrated) move the washing device 21 and the waste recovery device 24to predetermined positions, such as those illustrated in FIG. 1. Thus,ends of the nozzles 22 and 23 are directed towards the outer peripheryso that the discharge direction of the cleaning solution and the normalline of the substrate 1 define the prescribed angle illustrated in FIG.2. This operation is performed before the dye recording layer 2 hasfinished drying, so that washing is initiated within a predeterminedperiod of time after the dye recording layer 2 has finished drying.While the spinner head 13 is being rotated, the cleaning solution(discharge amount and discharge pressure having been adjusted by thepressure tank and the valve) is obliquely discharged onto the outerperipheral edge of the dye recording layer 2 through the two nozzles 22and 23, so that splashed cleaning solution does not adhere to the dyerecording layer 2.

[0055]FIG. 8 shows a state in which jetted cleaning solution (indicatedby an arrow) is scattered by centrifugal force from the substrate 1towards the waste recovery device 24. The cleaning solution is jettedonto a predetermined position of the outer periphery of the dyerecording layer 2. Because the rotational frequency of the spinner head13 during washing is generally set to be large, the solution (wasteliquid) is, as illustrated in FIG. 8, scattered in a roughly constantdirection. By disposing the waste recovery device 24 to face thatdirection, the cleaning solution (waste liquid) containing the dye canbe recovered by the waste recovery device 24.

[0056] As mentioned previously, when the outer peripheral edge of thedye recording layer 2 is washed/removed, the surface and the reversesurface of the substrate 1 may be simultaneously washed bysimultaneously operating the two nozzles 22 and 23. Alternatively, it isalso possible to first wash only the reverse surface (including part ofthe side surface of the substrate 1) after forming the dye recordinglayer 2 and then, after forming the reflective layer 3, wash the outerperipheral edge of the surface of the dye recording layer 2 of thesubstrate 1.

[0057] Although there are no particular limitations on the cleaningsolution (solvent) used for washing, examples thereof include diacetonealcohol, dibutyl ether, and 2,2,3,3-tetrafluoro-1-propanol. Diacetonealcohol is particularly preferable. These solvents are particularlyeffective when washing a cyanine dye recording layer. These solventsalso have an advantage in that they scarcely damage the substrate evenif the disc washed with these solvents is stored for a long period oftime.

[0058] In order to enhance washing efficiency, washing is preferablyconducted within 1.0 to 300 seconds, and more preferably within 3 to 100seconds, after the coating layer serving as the dye recording layer 2 isformed. When washing is initiated earlier than 1.0 seconds, the shape ofthe edge of the dye recording layer 2 is compromised due to insufficientdrying of the dye recording layer 2. When washing is initiated laterthan 300 seconds, it becomes difficult to remove the dye recording layer2 and may result in an inability to completely remove the dye recordinglayer 2 from the outer periphery of the substrate 1.

[0059] Discharge time of the cleaning solution is preferably 0.1 to 1.5seconds, more preferably 0.2 to 1.2 seconds, and even more preferably0.3 to 1.0 seconds. The amount of cleaning solution discharged ispreferably 0.2 to 3.0 ml, more preferably 0.4 to 2.0 ml, and even morepreferably 0.6 to 1.5 ml. The pressure at which the cleaning solution isdischarged is preferably 0.3 to 3.0 kg/cm², more preferably 0.5 to 2.0kg/cm², and even more preferably 0.7 to 1.7 kg/cm², to prevent thecleaning solution from being splattered.

[0060] Discharge pressure can be adjusted in accordance with thediameter of the nozzle, and the product of the nozzle diameter anddischarge pressure is preferably 0.2 to 2.4 mm·kg/cm², more preferably0.3 to 1.0 mm·kg/cm², and even more preferably 0.4 to 0.6 mm·kg/cm².

[0061] The rotational frequency of the spinner head 13 at the timedischarge of the cleaning solution begins is set to be 1000 to 10000rpm, so that the cleaning solution is not splashed onto the area of thedye recording layer 2 that is not to be removed. Preferably, therotational frequency is 2000 to 8000 rpm, and more preferably 3000 to6000 rpm. The rotational frequency of the spinner head 13 at the timethe cleaning solution is being spun off of the substrate is preferably3000 to 10000 rpm, more preferably 4000 to 8000 rpm, and even morepreferably 5000 to 7000 rpm.

[0062] Next, as illustrated in FIG. 5C, the reflective layer 3 isdisposed on the dye recording layer 2 to enhance reflectance,particularly when information recorded on the disc 30 is reproduced. Thematerial forming the reflective layer 3 comprises a substance having ahigh reflectance with respect to laser light. Examples thereof includemetals such as Mg, Se, Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Fe,Co, Ni, Ru, Rh, Pd, Ir, Pt, Cu, Ag, Au, Zn, Cd, Al, Ga, In, Si, Ge, Te,Pb, Po, Sn, and Bi, metalloids, and stainless steel. Preferable examplesinclude Cr, Ni, Pt, Cu, Ag, Au, Al, and stainless steel. These materialsmay be used singly or in combination of two or more. Alternatively, theymay be used in the form of alloys. Au, Ag, or alloys thereof areespecially preferable. The reflective layer 3 can be formed by, forexample, depositing, sputtering, or ion-plating the light reflectivematerial on the recording layer 2. The thickness of the reflection filmis generally 10 to 800 nm, preferably 20 to 500 nm, and even morepreferably 50 to 300 nm.

[0063] After the reflective layer 3 has been formed, washing may beperformed by jetting the cleaning solution from the nozzles 22 and 23 ofthe washing device 21 onto the outer peripheral edge (non-recordingregion) where the substrate has been exposed by removal of the dyerecording layer 2. Washing the non-recording region can be performed insubstantially the same manner as washing/removing the outer peripheraledge of the dye recording layer 2.

[0064] As illustrated in FIG. 2, when washing/removing the outerperipheral edge of the dye recording layer 2, ends of the nozzles 22 and23 are directed towards the outer periphery from the center of thesubstrate 1. However, when washing the non-recording region, it ispreferable for the mouth of the nozzle 22 (and 23) to be disposed to theouter side of the substrate 1 and facing the inner periphery, asillustrated in FIG. 9. By disposing the nozzle 22 in this manner, it ispossible to reliably wash the substrate 1 up to the boundary between thesubstrate 1 and the reflective layer 3. It should be noted that theconfiguration of the nozzle 22 is not limited as long as the conditionsbelow concerning the discharge direction of the cleaning solution aresatisfied, even when washing the non-recording region. Washing may evenbe performed using the straight nozzle 22′ illustrated in FIG. 3.

[0065]FIGS. 9 and 10 illustrate the position at which the nozzle 22 isdisposed when washing the non-recording region as respectively seen inan enlarged sectional view and a schematic planar view. The view in FIG.9 is seen from the side of a plane that extends in the normal linedirection of the substrate 1 and includes the straight line representingthe direction in which the cleaning solution is discharged from thenozzle 22. Although FIG. 9 only illustrates the position at which thenozzle 22 is disposed, the nozzle 23 may be disposed at a positionsimilar to the one illustrated in FIG. 2 to thereby wash the reversesurface of the substrate.

[0066] As illustrated in FIG. 9, when the non-recording region iswashed, the nozzle 22 is preferably disposed so that an angle θ₄ definedby the intersection between a discharge direction L_(e) of the cleaningsolution and the normal line L_(n) of the substrate 1 is 0 to 60°, andmore preferably 10 to 45°. The angle at which the nozzle 22 (and 23) isbent is adjusted to meet this condition. When the straight nozzle 22′ isused, the angle at which that nozzle 22′ is disposed is adjusted to meetthe same condition.

[0067] The range of the angle θ₄ is defined on the plane that extends inthe normal line direction of the substrate 1 and includes the straightline representing the discharge direction of the cleaning solution.

[0068] As illustrated in FIG. 10, when the substrate 1 is seen in planarview, the nozzle 22 (and 23) is disposed so that an angle θ₅, which isdefined by the intersection between a discharge direction L_(f) (whichis opposite to the direction of rotation R) of the cleaning solution anda straight line L_(g) connecting the center of the substrate 1 and themouth of the nozzle 22, is preferably 0 to 60°, and more preferably 10to 45°.

[0069] The distance from the mouth of the nozzle 22 to the substrate 1is preferably 0.3 to 5.0 mm, more preferably 0.5 to 3.0 mm, and evenmore preferably 0.7 to 2.0 mm. The diameter of the nozzle 22 ispreferably 0.1 to 0.8 mm, and more preferably 0.2 to 0.6 mm, in order tostably discharge the cleaning solution.

[0070] The rotational frequency of the spinner head 13 at the timedischarge of the cleaning solution is initiated is 3000 rpm or less inorder to reliably wash the dye recording layer 2 adhering to the outerperipheral edge. Additionally, it is preferable for the rotationalfrequency to become 50% or less than the rotational frequency of thespinner head 13 when discharge is initiated for washing/removing theouter peripheral edge of the dye recording layer 2.

[0071] As illustrated in FIG. 5D, the protective layer 4 is disposed onthe reflective layer 3 to physically and chemically protect the dyerecording layer 2. The protective layer 4 can also be disposed on theside of the substrate 1 where the dye recording layer 2 is not disposed,in order to improve resistance to damage and moisture. Examples ofmaterial usable for the protective layer 4 include inorganic substancessuch as SiO, SiO₂, MgF₂, SnO₂, and Si₃N₄, and also organic substancessuch as thermoplastic resins, thermosetting resins and UV-curableresins.

[0072] The protective layer 4 can be formed by, for example, laminatinga film obtained by extruding plastic material onto the reflective layer3 and/or the substrate 1, with an adhesive therebetween. The protectivelayer 4 may also be disposed by vacuum deposition, sputtering, orcoating. When the protective layer 4 comprises a thermoplastic resin orthermosetting resin, the protective layer 4 can be formed by dissolvingthe thermoplastic or thermosetting resin into a suitable solvent toprepare a coating solution, and thereafter coating the solution andallowing it to dry. When the protective layer 4 comprises a UV-curableresin, the protective layer 4 can be formed by using the UV-curableresin as it is or by dissolving it into a suitable solvent to prepare acoating solution, and thereafter coating the solution and curing thesame by irradiating the solution with UV light. Additives such asanti-static agents, antioxidants, and UV absorbents may be added to thesolution as needed. The protective layer 4 generally has a thickness of0.1 to 100 μm.

[0073] It should also be noted that the spin coater 10 of the inventioncan be used to form the undercoat and protective layers in the samemanner as the dye recording layer.

[0074] Method for Producing Optical Disc (2)

[0075] A second embodiment of the method of the invention, in which thenon-recording region is formed by later washing, will now be describedwith reference to FIGS. 11A to 11D.

[0076] As illustrated in FIG. 11A, the dye recording layer 2 is firstformed on the substrate 1 using the spin coater 10. Then, as illustratedin FIG. 11B, the reflective layer 3 is sputtered or ion-plated only onthe recording region of the dye recording layer 2 (i.e., excluding thenon-recording region).

[0077] Thereafter, as illustrated in FIG. 11C, the outer peripheral edge(the non-recording region) of the dye recording layer 2 iswashed/removed (later washing) with the washing device 21 of FIG. 2having the nozzles 22 and 23. Unless otherwise indicated, the laterwashing is performed in the same manner as the earlier washing describedabove, with the washing device 21 and in accordance with the conditionsdescribed below.

[0078] The two nozzles 22 and 23 used in the later washing are eachbent, as in the earlier washing, so that the cleaning solution isobliquely jetted onto the substrate 1. However, as long as the nozzle 22satisfies the conditions below concerning the method by which thecleaning solution is discharged, the shape thereof is not limited. Thestraight nozzles 22′ and 23′ can also be used.

[0079] Because the nozzles 22 and 23 (or the straight nozzles 22′ and23′) used in the later washing are disposed in the same manner as theyare in the earlier washing, description will be given of a case wherethe nozzles 22 and 23 are used.

[0080] As illustrated in FIG. 2, the nozzles 22 and 23 are preferablydisposed so that the angles θ₁ and θ₂ defined by the intersectionbetween the discharge directions L_(a) and L_(b) and the normal linedirection L_(n) of the substrate 1 are each 0 to 60°, and preferably 10to 45°. When the straight nozzles 22′ and 23′ are used, the angles atwhich they are disposed are adjusted in accordance with the angleconditions.

[0081] Although the nozzles 22 and 23 discharge the cleaning solutionwithin the angle range described above, they are at least disposed sothat they are not oriented towards the center of the substrate 1. Also,the ranges of angles θ₁ and θ₂ are defined on the plane that extends inthe normal line direction of the substrate 1 and includes the straightline representing the discharge direction of the cleaning solution.

[0082] As illustrated in FIG. 4, the nozzle 22 (and 23) is preferablydisposed so that, when seen in planar view, the angle θ₃ defined by theintersection between the discharge direction L_(c) of the cleaningsolution (facing the direction of rotation R) and the straight lineL_(d) connecting the center of the substrate and the mouth of the nozzleis 0 to 60°, and more preferably 10 to 45°.

[0083] The distance from the mouth of the nozzle 22 (and 23) to thesubstrate 1 is preferably 0.3 to 5.0 mm, more preferably 0.5 to 3.0 mm,and even more preferably 0.7 to 2.0 mm. The diameter of the nozzle 22 is0.1 to 0.8 mm, and more preferably 0.2 to 0.6 mm, in order to stablydischarge the cleaning solution.

[0084] By using the nozzles 22 and 23 (or the straight nozzles 22′ and23′) satisfying these conditions, as illustrated in FIG. 11C, the dyerecording layer 2 can be removed from the non-recording region.

[0085] In order to enhance washing efficiency, washing is preferablyconducted within 1.0 to 300 seconds, and more preferably within 3 to 100seconds, after the reflective layer 3 is formed. When washing isinitiated earlier than 1.0 seconds, the shape of the edge of the dyerecording layer 2 is compromised due to insufficient drying of the dyerecording layer, and may lead to edge peeling. When washing is initiatedlater than 300 seconds, it becomes difficult to remove the dye recordinglayer 2 by washing due to the dye recording layer 2 being overdried, andmay result in an inability to completely remove the dye recording layer2 from the outer periphery of the substrate 1 by washing.

[0086] Discharge time of the cleaning solution is preferably 0.1 to 1.5seconds, more preferably 0.2 to 1.2 seconds, and even more preferably0.3 to 1.0 seconds. The amount of cleaning solution discharged ispreferably 0.2 to 3.0 ml, more preferably 0.4 to 2.0 ml, and even morepreferably 0.6 to 1.5 ml. The pressure at which the cleaning solution isdischarged is preferably 0.3 to 3.0 kg/cm², more preferably 0.5 to 2.0kg/cm², and even more preferably 0.7 to 1.7 kg/cm², to remove the drieddye recording layer 2.

[0087] Discharge pressure can be adjusted in accordance with thediameter of the nozzle, and the product of the nozzle diameter anddischarge pressure is preferably 0.2 to 2.4 mm·kg/cm², more preferably0.3 to 1.0 mm·kg/cm², and even more preferably 0.4 to 0.6 mm·kg/cm².

[0088] The rotational frequency of the spinner head 13 at the timedischarge of the cleaning solution begins is set to be 1000 to 10000rpm, so that the cleaning solution is not splashed onto the area of thedye recording layer that is not to be removed. Preferably, therotational frequency is 2000 to 8000 rpm, and more preferably 3000 to6000 rpm. The rotational frequency of the spinner head 13 at the timethe cleaning solution is being spun off of the substrate is preferably3000 to 10000 rpm, more preferably 4000 to 8000 rpm, and even morepreferably 5000 to 7000 rpm.

[0089] Thereafter, as illustrated in FIG. 11D, the protective layer 4 isdisposed on the reflective layer 3 to physically and chemically protectthe dye recording layer.

[0090] According to the methods of the invention, the direction in whichthe cleaning solution is discharged and other washing conditions arespecified in washing/removing the dye recording layer from the outerperipheral edge of the substrate. Therefore, the non-recording region ofthe optical disc is completely washed and the shape of the edge isexcellent. As a result, an optical disc produced according to themethods of the invention has excellent storage stability and excellentrecording and playback characteristics.

EXAMPLES

[0091] The present invention will now be described in further detail byway of examples. However, the invention is not limited to theseexamples.

Example 1

[0092] A polycarbonate substrate (diameter: 120 mm; thickness: 1.2 mm;made by Teijin Limited; trade name: Panlite AD 5503) having formed inits surface a spiral pre-groove (track pitch: 1.6 μm; pre-groove width:0.4 μm; pre-groove depth: 0.16 μm) was obtained by injection molding.2.65 g of an indolenine dye (A), 0.265 g of an anti-fading agent (B),and 0.133 g of a bonding agent (made by Morton Limited, trade name:CA-139) were dissolved in 100 ml of 2,2,3,3-tetrafluoropropanol using anultrasonic vibrator (1800 W) over 10 hours, whereby a coating solutionfor forming a dye recording layer was prepared.

[0093] The coating solution was spin-coated on the entire surface havingthe pre-groove of the polycarbonate substrate, with rotational frequencybeing varied from 300 rpm to 4000 rpm, and dried to thereby form the dyerecording layer (pre-groove interior thickness: approximately 200 nm).The conditions under which the dye recording layer was formed were asfollows. Atmospheric temperature and humidity were 23° C. and 50% RH,the temperatures of the coating solution and the substrate were 23° C.,and exhaust wind speed was 0.1 m/sec.

[0094] Thereafter, using the nozzle 22 of the washing device 21illustrated in FIG. 2, the outer peripheral edge of the dye recordinglayer was washed/removed to thereby form a non-recording region. Thewashing conditions were as shown in Table 1, and diacetone propanol wasused as the cleaning solution. TABLE 1 Comparative ComparativeComparative Comparative Example 1 Example 1 Example 2 Example 3 Example4 Example 2 Example 3 Θ₁(°) 10 10 10 −30 70 10 10 Θ₃(°) 0 0 0 0 0 −30 70Number of nozzles 1 1 1 1 1 1 1 Discharge pressure 1 1 1 1 1 1 1(kg/cm²) Nozzle diameter (mm) 0.3 0.3 0.3 0.3 0.3 0.3 0.3 Discharge time(s) 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Rotational frequency 6000 6000 6000 60006000 6000 6000 during discharge (rpm) Rotation time during 0.8 0.8 0.80.8 0.8 0.8 0.8 discharge (s) Rotational frequency 6000 6000 6000 60006000 6000 6000 during spin off (rpm) Rotation time during spin 0.5 0.50.5 0.5 0.5 0.5 0.5 off (s) Discharge amount (ml) 0.9 0.9 0.9 0.9 0.90.9 0.9 Lapse of time after forming 30 500 0.1 30 30 30 30 recordinglayer (s)

[0095] Next, a reflective layer having a thickness of 150 nm was formedby sputtering Ag onto the dye recording layer. A UV-curable resin (tradename: SD-318; made by Dainippon Ink and Chemicals, Inc.) was spin-coatedon the reflective layer while rotational frequency was varied from 50rpm to 5000 rpm. Ultraviolet rays were then irradiated from a highpressure mercury lamp to thereby cure the UV-curable resin and form aprotective layer having a thickness of 8 μm.

[0096] A CD-R optical information recording medium (disc) comprising thesubstrate having disposed thereon the dye recording layer, the lightreflective layer, and the protective layer was thereby produced (CD-R ofExample 1). The non-recording region of the obtained CD-R was completelywashed and the configuration of the edge portion was excellent. Also, atest for storability was conducted by storing the CD-R at 80° C. and in85% humidity for 100 hours. Recording and playback characteristics ofthe CD-R were evaluated before and after the test for storability usinga machine for evaluation “OMT2000” (made by Pulsteck Limited). The CD-Rhad excellent storage stability and excellent recording/playbackcharacteristics.

Examples 2 and 3

[0097] Optical information recording media (CD-Rs) of Examples 2 and 3were produced in the manner as in Example 1, except that washingconditions were changed as shown in Table 1.

[0098] The non-recording region of the CD-R of Example 2 was completelywashed, and the shape of the edge was excellent. Slight splattering ofthe cleaning solution was observed, but not to the extent that wouldpresent a practical problem. The non-recording region of the CD-R ofExample 3 was completely washed, and the shape of the edge was slightlycompromised but not to the extent that would present a practicalproblem.

Comparative Examples 1 to 4

[0099] Optical information recording media (CD-Rs) of ComparativeExamples 1 to 4 were produced in the same manner as in Example 1, exceptthat washing conditions were changed as shown in Table 1.

[0100] The non-recording regions of the CD-Rs of Comparative Examples 1and 4 could not be sufficiently washed, and it was visually confirmedthat dye remained in the non-recording region. It was also confirmedthat the shape of the edge of the CD-R of Comparative Example 2 wascompromised. With respect to the CD-R of Comparative Example 3,splattering could not be sufficiently prevented and, although evaluationwas conducted in the same manner as in Example 1, recording errorsoccurred at the outer periphery.

Example 4

[0101] A polycarbonate substrate (diameter: 120 mm; thickness: 1.2 mm;made by Teijin Limited; trade name: Panlite AD 5503) having formed inits surface a spiral pre-groove (track pitch: 1.6 μm; pre-groove width:0.4 μm; pre-groove depth: 0.16 μm) was obtained by injection molding.2.65 g of the indolenine dye (A) shown above, 0.265 g of the anti-fadingagent (B) shown above, and 0.133 g of a binding agent (made by MortonLimited; trade name: CA-139) were dissolved in 100 ml of2,2,3,3-tetrafluoropropanol using an ultrasonic vibrator (1800 W) over10 hours, to thereby prepare a coating solution for forming a recordinglayer.

[0102] The coating solution was spin-coated on the entire surface havingthe pre-groove of the polycarbonate substrate, with rotational frequencybeing varied from 300 rpm to 4000 rpm, and dried to thereby form the dyerecording layer (pre-groove interior thickness: approximately 200 nm).The conditions under which the dye recording layer was formed were asfollows. Atmospheric temperature and humidity were 23° C. and 50% RH,the temperatures of the coating solution and the substrate were 23° C.,and exhaust wind speed was 0.1 m/sec.

[0103] Next, a reflective layer having a thickness of 150 nm was formedby sputtering Ag onto the recording region of the dye recording layer(and not the non-recording region).

[0104] Thereafter, using the nozzle 22 of the washing device 21illustrated in FIG. 2, the outer peripheral edge of the dye recordinglayer was washed/removed to thereby form a non-recording region. Thewashing conditions were as shown in Table 2, and diacetone propanol wasused as the cleaning solution. TABLE 2 Comparative ComparativeComparative Comparative Example 4 Example 5 Example 6 Example 7 Example8 Example 5 Example 6 Θ₁(°) 40 40 40 −30 70 40 40 Θ₃(°) 0 0 0 0 0 −30 70Number of nozzles 1 1 1 1 1 1 1 Discharge pressure 1.5 1.5 1.5 1.5 1.51.5 1.5 (kg/cm²) Nozzle diameter (mm) 0.4 0.4 0.4 0.4 0.4 0.4 0.4Discharge time (s) 0.9 0.9 0.9 0.9 0.9 0.9 0.9 Rotational frequency 450450 450 450 450 450 450 during discharge (rpm) Rotation time during 0.10.1 0.1 0.1 0.1 0.1 0.1 discharging (s) Rotational frequency 5900 59005900 5900 5900 5900 5900 during spin off (rpm) Rotation time for spin 11 1 1 1 1 1 off (s) Discharge amount (ml) 0.8 0.8 0.8 0.8 0.8 0.8 0.8Lapse of time after forming 10 500 0.15 10 10 10 10 reflective layer (s)

[0105] Next, a UV-curable resin (trade name: SD-318; made by DainipponInk and Chemicals, Inc.) was spin-coated on the reflective layer whilerotational frequency was varied from 50 rpm to 5000 rpm. Ultravioletrays were then irradiated from a high pressure mercury lamp to therebycure the UV-curable resin and form a protective layer having a thicknessof 8 μm.

[0106] A CD-R optical information recording medium (disc) comprising thesubstrate having disposed thereon the dye recording layer, the lightreflective layer, and the protective layer was thereby produced (CD-R ofExample 4). The non-recording region of the obtained CD-R was completelywashed and the configuration of the edge portion was excellent. Also, atest for storability was conducted by storing the CD-R at 80° C. and in85% humidity for 100 hours. Recording and playback characteristics ofthe CD-R were evaluated before and after the test for storability usinga machine for evaluation “OMT2000” (made by Pulsteck Limited). The CD-Rhad excellent storage stability and excellent recording/playback.

Examples 5 and 6

[0107] Optical information recording media (CD-Rs) of Examples 5 and 6were produced in the same manner as in Example 4, except that washingconditions were changed as shown in Table 2.

[0108] The non-recording regions of the CD-Rs of Examples 5 and 6 werecompletely washed, and the shapes of their edges were compromised,although not to the extent that would present a practical problem.

Comparative Examples 5 to 8

[0109] Optical information recording media (CD-Rs) of ComparativeExamples 5 to 8 were produced in the same manner as in Example 4, exceptthat washing conditions were changed as shown in Table 2.

[0110] The non-recording regions of the CD-Rs of Comparative Examples 5,8 and 9 could not be sufficiently washed, and it was visually confirmedthat dye remained in the non-recording regions. With respect to the CD-Rof Comparative Example 6, it was confirmed that the shape of its edgewas compromised.

What is claimed is:
 1. A method for producing an optical informationrecording medium, comprising at least the steps of: coating a solutionfor forming a dye recording layer onto a surface of a rotatingdisc-shaped resin substrate; and discharging a cleaning solution from anozzle onto a peripheral edge to remove the dye recording layer from theperipheral edge, wherein discharge of the cleaning solution is initiated1.0 to 300 seconds after completion of the coating, and the nozzle isdisposed on a plane that extends in a normal line direction of thesubstrate and includes a straight line representing a dischargedirection of the cleaning solution, so that an angle defined by thedischarge direction and the normal line is 0 to 60°.
 2. The method ofclaim 1, wherein, in removing the dye recording layer, when thesubstrate is viewed from above, a virtual line that extends from adischarge mouth of the nozzle in the discharge direction is located on arotation direction side of a straight line connecting a center of thesubstrate and the discharge mouth of the nozzle, with an angle definedbetween the straight line and the virtual line being 0 to 60°.
 3. Themethod of claim 1, wherein the angle defined by the discharge directionand the normal line is 10 to 45°.
 4. The method of claim 1, wherein thedistance from a discharge mouth of the nozzle to the substrate is 0.3 to5.0 mm.
 5. The method of claim 1, wherein discharge time of the cleaningsolution is 0.1 to 1.5 seconds.
 6. The method of claim 1, wherein theamount of the cleaning solution discharged is 0.2 to 3.0 ml.
 7. Themethod of claim 1, wherein discharge pressure of the cleaning solutionis 0.3 to 3.0 kg/cm².
 8. The method of claim 1, wherein the cleaningsolution is discharged by two nozzles that are respectively disposed atopposing positions above and below the substrate.
 9. The method of claim1, wherein discharge of the cleaning solution is initiated within 3 to100 seconds after completion of the coating.
 10. The method of claim 2,wherein the angle defined by the straight line and the virtual line is10 to 45°.
 11. A method for producing an optical information recordingmedium, comprising at least the steps of: coating a solution for forminga dye recording layer onto a surface of a rotating disc-shaped resinsubstrate; coating a reflective layer on the formed dye recording layer;and discharging a cleaning solution from a nozzle onto a peripheral edgeto remove the dye recording layer from the peripheral edge, whereindischarge of the cleaning solution is started 1.0 to 300 seconds aftercompletion of the coating of the reflective layer, and the nozzle isdisposed on a plane that extends in a normal line direction of thesubstrate and includes a straight line representing a dischargedirection of the cleaning solution, so that an angle defined by thedischarge direction and the normal line is 0 to 60°.
 12. The method ofclaim 11, wherein, in removing the dye recording layer, when thesubstrate is viewed from above, a virtual line that extends from adischarge mouth of the nozzle in the discharge direction is located on arotation direction side of a straight line connecting a center of thesubstrate and the discharge mouth of the nozzle, with an angle definedby the straight line and the virtual line being 0 to 60°.
 13. The methodof claim 11, wherein the angle defined by the discharge direction andthe normal line is 10 to 45°.
 14. The method of claim 11, wherein thedistance from a discharge mouth of the nozzle to the substrate is 0.3 to5.0 mm.
 15. The method of claim 11, wherein discharge time of thecleaning solution is 0.1 to 1.5 seconds.
 16. The method of claim 11,wherein the amount of the cleaning solution discharged is 0.2 to 3.0 ml.17. The method of claim 11, wherein discharge pressure of the cleaningsolution is 0.3 to 3.0 kg/cm².
 18. The method of claim 11, wherein thecleaning solution is discharged by two nozzles that are respectivelydisposed at opposing positions above and below the substrate.
 19. Themethod of claim 11, wherein discharge of the cleaning solution isinitiated within 3 to 100 seconds after completion of the coating of thereflective layer.
 20. The method of claim 12, wherein the angle definedby the straight line and the virtual line is 10 to 45°.